I. Field of the Invention
The present invention, which is a continuation-in-part of application Ser. No. 354,713 for an ASPHERIC LENS BLANK relates generally to spectacle lens blanks and, more particularly, to a thin aspheric spectacle lens blank.
II. Description of the Prior Art
The previously known spectacle lens blanks typically comprise a spherical front convex surface and a spherical concave rear surface. The front and rear surfaces of the lens are formed on different radii of curvature thus providing the desired light refraction for the lens. This refraction can vary over the range of positive amounts thus acting to correct farsightedness.
Although previously known positive refraction lens have adequately corrected vision for users, they necessarily result in a relatively thick central portion of the lens. These previously known lenses are not only relatively heavy and therefore uncomfortable to wear, but are also unsightly. Such thick lenses also exhibit chromatic aberration around the outer periphery of the lens for high power lenses, and spherical aberration.